Premature delivery accounts for 12% of all births in the United States and is identified as the leading cause of perinatal morbidity and mortality. Despite advancements in medicine and technology, the incidence of preterm birth has not decreased in recent years and knowledge of the physiological mechanism of the onset and propagation of uterine contractions of preterm labor remains incomplete. Current uterine monitoring methodologies have low positive predictive values and lack the sensitivity to study and plan appropriate therapeutic interventions. We propose to use a non-invasive technology device called SARA (Squid Array for Reproductive Assessment) to study the physiological mechanism of uterine contractions by non-invasively recording magnetic fields (Magnetomyography-MMG) corresponding to electrical activity of the uterine smooth muscle. SARA was designed to cover the entire maternal abdomen with 151 individual sensors. By simultaneously recording uterine MMG from multiple points, we gain access to spatial-temporal information unattainable prior to SARA. Its location within the labor and delivery unit provides unique access to preterm patients. The array design provides non-invasive magnetic recording of the initiation and propagation of uterine electrical activity resulting from excitation and propagation of action potentials in uterine smooth muscle cells. The detailed spatial-temporal resolution of SARA can determine regions of localized activation, propagation velocity and direction, and spread of activity as a function of distance. This data will be used to define physiological steps leading to organized uterine contractions, thus providing the basis for the development of a methodology to accurately predict the onset of active labor. New insight into the initiation and propagation of uterine electrophysiological activity may also provide innovative approaches toward suppression of preterm labor and induction of labor. The specific aims of the proposed project are: 1. Determine if serial uterine MMG measurements can be used to predict the onset of labor in patients with prolonged premature rupture of membranes. 2. Determine if uterine MMG recordings can be used to discern false preterm labor from true preterm labor. In addition, we plan to compare the predictive power of MMG to standards tests for pre-term labor. PUBLIC HEALTH RELEVANCE:A new non-invasive technology to better diagnosis of preterm labor which can lead to development of strategies that can prevent or control preterm labor thereby reducing the incidence of preterm birth.